ObjectiveIncreased use of CT imaging has been identified as a key component of unsustainable rising healthcare costs in the USA and globally. Understanding evidence and its relation to imaging coverage policies can help identify patterns of variation to better inform high value care initiatives. This cross-sectional study evaluates regional differences in US utilisation of cardiac coronary tomography angiography (CCTA) and compares use in the USA and England.DesignWe determined differences in CCTA order rates by US Medicare region and compared order rates in the US and England, compared CT scanner prevalence in the USA and UK, and reviewed the CCTA coverage policies for each region.SettingThe US and the UK.ParticipantsMedicare Coverage Database; Medicare 2018 Part B data; National Health Services 2018 data.InterventionsCCTA orders, CT scanner prevalence.Main outcome measuresCCTA orders per beneficiary, CT scanner prevalence, CCTA policy variation.ResultsWe found that CCTA coverage policies are more permissive in the UK compared with the USA. However, CT scanner prevalence per beneficiary is four times greater in the USA than the UK. There was significant variation in number of CCTA ordered per 100 000 beneficiaries between regions in England and the USA, ranging from 74 to 313 in the US and 57–317 in England.ConclusionsThere is significant geographical variation in use of CCTA in both the USA and England, although overall use does not differ significantly between both countries. Similarities in order rates, despite a much higher CT scanner density in the USA, may be related to more permissive guidelines around use of CCTA in the UK. Variation in both countries may also reflect the lack of high-quality clinical outcomes data for use of CCTA, underscoring opportunities for more evidence and evidence-based policy to promote appropriate use of CCTA imaging.